Method For Growth Of GaN Single Crystal, Method For Preparation Of GaN Substrate, Process For producing GaN-Based Element, and GaN-Based Element

Grown on the substrate using a metal buffer layer grown GaN-based thin film (thick). (A) 120 is formed on a sapphire substrate deposition Cr, Cu or the like metal buffer layer 210. (B) for depositing a metal on a sapphire substrate 120 a buffer layer 210 of the substrate obtained, nitriding treatment in an ammonia gas atmosphere, to form the metal nitride layer 212. (C) the treated metal nitride buffer layer 210, 212, 222 grown GaN buffer layer. (D) Finally, growing a GaN single crystal layer 220. The single crystal GaN layer 220 may be grown in a variety of desired thickness. Substrate prepared by the above process, may be prepared by selective chemical etching from the supporting substrate, it was also prepared GaN-based light emitting diodes, laser diodes can be used as a GaN template substrate for use.